Neurons are targets for damaging stimuli, which may trigger cell death and in consequence serious neurological diseases. Interestingly, most neurons survive minor damages which they are challenged with during the life span. Therefore one can propose existence of a mechanism that helps neurons to survive the initial injury and resume proper functions after an insult. Identification of this mechanism may result in development of treatments that would harness the intrinsic neuronal defense machinery to combat against neurological diseases. An important damaging stimulus in the CNS is oxidative stress. It exerts its toxic effects at least in part through injury of DNA whose integrity is critical for proper neuronal survival. Indeed, neurons are very sensitive to DNA damage. Interestingly, DNA damaging agents that are used in cancer therapy frequently produce neurological side effects. Our recently published results indicate that Extracellular Signal Regulated Kinase 1/2 (ERK1/2) is activated in rat cortical neurons by a neurotoxic DNA-damaging drug, cisplatin (CPDD) (J Biol Chem 278:43663-43671). Furthermore, we have found that inhibition of ERK1/2 pathway enhances toxic response to CPDD. Consequently, the general aim of our proposal is testing a hypothesis that neuronal DNA damage activates ERK1/2 to suppress neuronal death and to enhance repair of the cellular damage. We will approach this goal by (i) identification of the mechanism behind ERK1/2 mediated protection against DNA damage, (ii) dissection of the pathway linking DNA damage and survival signaling by ERK1/2, (iii) identification of factors which could enhance defensive signaling by ERK1/2 in neurons and finally by (iv) evaluation of ERK1/2 activation as a general compensatory response to diverse forms of DNA injury. To realize the proposal we will use cultured rat primary neurons. The proposed research may result in identification of new drug targets for treatment of neurological diseases and/or deleterious neurological side effects of cancer therapy.